One Method of Determination of the Effective Absorption Coefficient in Pulsed Laser Irradiation of Metals

Evtushenko, A. A.; Ivanik, E. G.; Rożniakowski, K.

doi:10.1023/b:joep.0000003208.98698.7c

Cited by 6 publications

(6 citation statements)

References 4 publications

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“…Greatly diminished in this case is the role of electron thermal conduction as the main mechanism of transferring into the target the energy absorbed by conduction electrons. Second, under high-intensity laser irradiation the reflectivity of a metal surface is not a constant value: beginning from some threshold intensity (according to different estimates, I < 100 MW cm -2 [1,17,18]), the initially high reflectivity (0.7 - 0.99 in the optical range, depending on the type of metal) may decrease several-fold during the irradiation, thereby lowering the absorptivity to 50 % of the incident radiation energy [1]. Third, owing to a sharp lowering of the electrical conduction of metals observed in their rapid heating to temperatures of 1000 - 1500 K, the depth of radiant energy penetration into the metals becomes several times longer.…”

Section: Vapour-plasma Substance Production At Atmospheric Pressurementioning

confidence: 99%

Possibility of applying a hydrodynamic model to describe the laser erosion of metals irradiated by high-intensity nanosecond pulses

Kozadaev¹

2014

Quantum Electron.

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We report the results of experimental investigations of the production and development of plasma-vapour plumes upon irradiation of metal targets by nanosecond (10 -100 ns) pulses with a high (10 8 -10 10 W cm -2 ) power density under atmospheric conditions. The transition from a quasi-stationary thermal mechanism of metal erosion to an explosion hydrodynamic one takes place when the radiation power density increases from 10 8 to 10 9 W cm -2 . The resultant experimental information is extremely important for the laser deposition of metal nanostructures under atmospheric conditions, which is possible only for power densities of 10 8 -10 9 W cm -2 .

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Section: Vapour-plasma Substance Production At Atmospheric Pressurementioning

confidence: 99%

Possibility of applying a hydrodynamic model to describe the laser erosion of metals irradiated by high-intensity nanosecond pulses

Kozadaev¹

2014

Quantum Electron.

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“…It should be noted that the initially high coefficient of reflection of optical radiation by metals (R 0.8-0.99 for a laser-radiation wavelength of 1064 nm [11]) under intense laser action can sharply decrease, reducing the integral dose of energy absorbed by the target to 50% of the optical energy reaching the target surface [12]. In connection with the fact that the leading-edge time is shorter than the characteristic times of thermal relaxation in metals, the absorbed energy does not penetrate (by heat conduction) deep into the target material.…”

Section: Character Of Destruction Of Metallic Targets By Submicrosecomentioning

confidence: 99%

Formation and investigation of optical media containing gold nanoparticles

Goncharov

Kozadaev

Shiman

et al. 2012

J Eng Phys Thermophy

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Consideration has been given to certain aspects of condensation processes occurring in laser-induced erosion plumes of metals and giving rise to fluxes of metallic nanoparticles. Samples of colloidal solutions of gold and gold-containing polymer films have been produced as a result of precipitation of nanoobjects formed in laser erosion of gold into aqueous and polymer-containing media. The experimental samples formed have been comprehensively investigated using optical spectroscopy and transmission and scanning electron microscopy.Keywords: laser synthesis of metal nanoparticles, erosion laser plume, colloidal solution of gold, gold-containing polymer film, surface plasmon resonance.Introduction. The increasing practical interest currently expressed in methods of formation and investigation of isolated metal nanoparticles is due to the wide range of advantages which are offered by traditional media modified by metallic nanostructures. Ultradisperse metal-containing media may exhibit exotic electrical, magnetic, optical, thermophysical, chemical, biological, and other properties [1-3]. The mentioned features are determined by the presence of the so-called dimensional effects in isolated metal particles with a diameter less than 100 nm [2].Numerous methods of formation of ultradisperse metal-containing media have been developed to date. All these approaches can be subdivided into three conventional groups, as far as the principle of formation is concerned, i.e., physical (e.g., [4,5]), chemical [6,7], and combination (physicochemical) [8] ones. The enumerated methods offer their own advantages and drawbacks and can be applied to the solution of certain technological problems.However, properties characteristic of gold as a metal (chemical stability, inertia, relative infusibility, and high specific weight) make it impossible to use in full measure most of the existing methods of obtaining nanostructures. Chemical methods traditionally used for these purposes are rather labor-intensive and expensive [7]. We can consider the technique of laser synthesis of colloidal solutions of gold [9] as an alternative solution; this technique is based on the fact that the products of laser erosion from gold targets enter trapping media whose composition may vary. The use of today's frequency-modulated lasers for production of gold-containing colloids makes it possible to improve the competitiveness of the procedure of laser synthesis compared to other techniques of formation of ultradisperse metalcontaining media. Additional advantages of the indicated technique are the technological simplicity of the synthesis plant, the possibility of controlling the process of synthesis on line, and the high rates of formation of colloids. Character of Destruction of Metallic Targets by Submicrosecond Laser Pulses.In the process of exposure of metals to intense submicrosecond optical radiation pulses in a thin surface region of the target, part of the pulse is absorbed by conduction electrons [10]. It should be noted that the initially high co...

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“…The influence of intensive nanosecond optical radiation pulses on the silver target causes the partial absorption of the pulse energy by conduction electrons in the thin subsurface zone [7]. It's important to note that primarily the high reflectivity coefficient of optical radiation by silver surfaces (R=0.97 for л=1064 nm [8]) may drastically drop if exposed intensively by laser and, as a result, may increase the integrated dose of the absorbed energy to 50% of the optical energy that reached the surface of the target [9]. Considering that the duration of the leading edge of pulse is less than the thermal relaxation time for silver, the excess energy has no time to penetrate deep into the target at the expense of thermal conductivity.…”

Section: The Character Of Silver Targets Destruction Under Action Of Nanosecond Laser Pulsesmentioning

confidence: 99%

Laser synthesis of optical media with silver nanoparticles by nanosecond pulses at air

Goncharov

Kozadaev

Shchehrykovich

2011

Opt. Mem. Neural Networks

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One Method of Determination of the Effective Absorption Coefficient in Pulsed Laser Irradiation of Metals

Cited by 6 publications

References 4 publications

Possibility of applying a hydrodynamic model to describe the laser erosion of metals irradiated by high-intensity nanosecond pulses

Possibility of applying a hydrodynamic model to describe the laser erosion of metals irradiated by high-intensity nanosecond pulses

Formation and investigation of optical media containing gold nanoparticles

Laser synthesis of optical media with silver nanoparticles by nanosecond pulses at air

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